The present invention relates generally to a brake arrangement and brake-operating assembly. More specifically, the invention relates to brake arrangements for machines, such a wheeled loaders, dumpers and the like, are used to brake the movement of the machine and to prevent the machine from moving from a standstill.
Brake arrangements of the type generally referred to above may take the form of a parking brake. Some machines, such as wheeled loaders and dumpers, are provided with two brake pedals for this function which are positioned in such a manner in a driver""s cab of the machine that the driver can use either the right foot or the left foot to brake the machine. It is previously known to configure such a brake arrangement in the form of a multiplate clutch on the output transmission shaft of a wheeled loader. The multiplate clutch functions as a parking brake and comprises a number of plates surrounded by a fluid present in the multiplate brake. When the parking brake is activated, the plates bear against discs in the multiplate brake so that the plates, and thus the output transmission shaft, are secured utilizing friction. When the parking brake is deactivated, the plates are not in contact with the discs in the multiplate brake, but instead rotate freely in the surrounding fluid. It has been found, however, that the viscous losses in such known brake arrangements are considerable when the parking brake is deactivated and the vehicle is driven forwards. These losses lead to increased fuel consumption by the machine. The viscous losses occur when the plates rotate in the surrounding fluid.
It is also previously known to provide a mechanical connection between two brake pedals of a wheeled loader in the form of a connecting shaft. The first brake pedal is connected to a valve which is arranged to control the flow of hydraulic fluid from a pressure source to brake cylinders of the machine. When the second brake pedal is pressed down, the valve connected to the first pedal will be acted on by virtue of the fact that the connecting shaft between the brake pedals ensures that the first brake pedal is also pressed down. A disadvantage of this known brake-operating assembly is that the connecting rod occupies otherwise usable space on the floor of the driver""s cab.
In view of the above described deficiencies associated with conventionally designed braking arrangements, the present invention has been developed. These enhancements and benefits are described in greater detail hereinbelow with respect to several alternative embodiments of the present invention.
The present invention in its several disclosed embodiments alleviates the drawbacks described above with respect to conventionally designed braking arrangements and incorporates several additional beneficial features.
One object of the present invention is to produce a brake arrangement which is essentially loss-free when the brake arrangement is activated. That is, such a brake arrangement results in imperceptible losses because the locking element engages with the output shaft only when the machine is at a standstill and there is no contact between these components when the output shaft is rotating. The result is that the locking element does not cause any power losses during operation of the machine. By simultaneously engaging the gear clutches for the respective gear steps braking of the vehicle can be brought about by means of the brake arrangement. The brake arrangement can thus be used as a parking brake which is activated when the machine is driving along or at a standstill.
Another object of the present invention is to produce a brake-operating assembly which eliminates a mechanical connection between two brake pedals and thus affords a greater amount of free floor space in the driver""s cab. Among other things, this increases the mobility of the driver and thus affords the driver greater comfort. The brake-operating assembly according to the present invention also affords a simpler construction and thus easier mounting in the machine. The brake-operating assembly also leads to greater safety because a valve element is arranged at each brake pedal.